This invention relates to valve assemblies and valve means.
The invention is more particularly concerned with hydraulic valve assemblies and valve means for use in controlling flow of hydraulic fluid between a source of pressure and an hydraulic strut or the like.
In vehicle leveling systems, an hydraulic strut is connected between the vehicle chassis and suspension to change the height of the suspension relative to the chassis, such as in response to changes in loading of the vehicle. An electrical height sensor detects variation in the height of the vehicle body and this provides an output to the hydraulic system supplying the strut. In addition to adjusting the height, the strut is usually required to provide a shock absorbing function. For this to be effective, there must always be a certain minimum pressure in the strut. There is a tendency for fluid pressure to be lost from these struts over time which requires expensive servicing in order to maintain optimum ride quality.
It is an object of the present invention to provide a valve assembly and valve means that can be used to alleviate this problem.